Studies on controlled release formulations of a macrolide antibiotic drug: Influence of HPMC of different grades as matrix former

In the present study, several combinations of different grades of hydroxy propyl methyl cellulose (HPMC) such as HPMC-K4M, HPMC-K15M, HPMC-K100M as hydrophilic polymers and hydrophobic polymer like ethyl cellulose(EC) are used to prepare the matrix tablets that resulted in desired and controlled drug release profile. Hydrophobic polymers provide several advantages including good stability at varying pH ranges and effectively retard the release of water soluble drug(s) along with hydrophilic polymers. Erythromycin ethylsuccinate is a model drug and having short half-life of 1.5 hours. Tablets containing 100 mg of drug were formulated by wet granulation. Pre-compression and post-compression parameters were evaluated for all the formulations, which are in the acceptable range. The dissolution data were fitted into zero-order, first-order, Higuchi and Korsemeyer–Peppas models to identify the pharmacokinetics and drug release mechanism. The optimized formulation (F5) prepared with EC: HPMC-K4M in the ratio 10 mg: 5 mg show 99.02% drug release in 24 hours, which is comparable with marketed sample. Kinetic results reveal that all formulations followed zero order. Hence, it can be concluded that the use of low viscous hydrophilic polymer can extend the release of drug up to 24 hours.